In the drilling and completion industry, the formation of boreholes for the purpose of production or injection of fluid is common. The boreholes are used for exploration or extraction of natural resources such as hydrocarbons, oil, gas, water, and alternatively for CO2 sequestration.
Composite frac plugs generally have an open inner diameter that is occluded by a ball dropped from the surface. The reason for this arrangement is that if the guns don't fire after the plug is set, then the open inner diameter will permit pumping another set of guns downhole without mobilizing coiled tubing to open a flow path. In a “plug and perf” operation, a bottom hole assembly (“BHA”) is run on wircline into a borchole that is typically cased and cemented and could include both horizontal and vertical sections. The BHA includes an isolation tool (the frac plug), a setting tool, and one or more perforation guns. The setting tool is actuated for packing off a production zone with the isolation tool. The one or more perforation guns are then positioned in the borehole and triggered by a signal sent down the wireline. Typically, balls are used for the isolation tools as such ball-accepting isolation tools provide fluid communication with lower zones, which enables sufficient fluid flow for redeploying the perforation guns in the event that they do not fire properly. After perforation, the BHA (excluding the isolation tool) is pulled out and a ball is dropped from surface for engaging a seat of the isolation tool for impeding fluid flow therethrough. While the process works adequately, it requires a significant amount of time and fluid to pump a ball downhole. Bridge plugs are occasionally used instead of ball type frac plugs, but these bridge plugs do not enable the aforementioned redeployment of failed perforation guns.
The art would be receptive to improved devices and methods for occluding a frac plug after firing of perforating guns.